Fluid heater cleaners



Dec. 18, 1962 Filed Aug. 24, 1960 R. H. EVANS FLUID HEATER CLEANERS \xOu E i (Darm Dec. 18, 1962 R. H. EVANS FLUID HEATER CLEANERS 2Sheets-Sheet 2 Filed Aug. 24, 1960 United States Patent Ohee 3,@685'?Patented Dec. 18, 1952 FLUED HEATER CLEANERS Richard Henry Evans,London, England, assigner to Bahcocli 8.' Wilcox Limited, London,England, a company of Great Britain Filed Ang. 24, 1960, Ser. No. 51,570Claims priority, application Great Britain Aug. 23, 1959 3 Claims. (Cl.15-31'7) This invention relates to fluid heater cleaners of the kindcomprising a nozzle tube adapted to be projected for operation from aretracted position.

The specification of United Kingdom patent specification No. 636,052describes a fluid heater cleaner of the above kind and in which a nozzletube is projected through a considerable distance which in practicecould be up to say 27 feet.

lt has been found that when the construction of specification No.636,052 is applied to nozzle tubes which require to be projected throughan even greater distance, say 37 feet, the leading end of the nozzletube, lwhich is unsupported, tends to deflect a greater amount than ispermissible.

An object of the present invention is the provision of a fluid heatercleaner having a nozzle tube less subject to undesirable deflection ofits outer unsupported end.

The invention includes a lluid heater cleaner including a nozzle tube Somounted as to permit the nozzle tube to be projected to an operativeposition over a substantial distance from, and returned to, a retractedposition, wherein the nozzle tube is provided with an outer wall and aninner wall defining an axially extending annular passage between the twowalls arranged for the passage of cleaning fluid flowing to thedischarge nozzle or nozzles provided on the nozzle tube and diver-tedfrom a central region of the nozzle tube, whereby a desired velocity offlow of cleaning fluid over the inner surface of the outer wall can beobtained despite a relatively large cross sectional area of the bore ofthe nozzle tube.

The invention also includes a fluid heater celaner including an outernozzle tube, and an inner cleaning fluid supply tube, the two tubesbeing telescopically arranged to permit the nozzle tube to be projectedto an operative position over a substantial distance from, and returnedto, a retracted position, wherein the nozzle tube is provided with anouter wall and an inner wall defining an axially extending annularpassage between the two walls arranged for the passage of cleaning fluidflowing to the discharge nozzle or nozzles provided on the nozzle tubeand diverted from a central region of the nozzle tube, whereby a desiredvelocity of ilow of cleaning uid over the inner surface of the outerwall can be obtained despite a relatively large cross sectional area ofthe bore of the nozzle tube.

The invention will nov be described, by way of example, with referenceto the accompanying drawings, in which:

FEGURE l, which is partly diagrammatic, shows in side elevation and-withparts broken away the general arrangement of two adjacent similar fluidheater cleaners both embodying the present invention, but at differentpositions in their cycle of operation;

FIGURE 2 is a sectional side elevation of a nozzle tube shown in FIGUREl, but drawn to a much larger scale than in FiGURE l;

FGURE 3 is a transverse sectional view taken on the line lll-lll ofFGURE 2;

FiGURE 4 is a transverse sectional view of part of'an I-beam and a feedtube shown in FIGURE 1 and illustrates an intermediate support memberfor the feed tube; and

FIGURE 5 is a sectional side elevation "taken on the line V--V of FIGURE4 but with the parts in a diterent operative position.

Reference should be made to United Kingdom patent specification No.636,052 for a full description of the construction and operation of thetwo similar uid heater cleaners 1A and 1B shown in FIGURE 1. The presentinvention relates -to a modified form for the nozzle tubes 3 possessingadvantages over the form of nozzle tube shown in that priorspecification.

Briefly, the cleaner illustrated includes a nozzle tube 3 which may beadvanced through an aperture in a wall 5 of the casing of the fluidheater with which the cleaner is associated, from the retracted positionof the upper cleaner 1A of the two similar cleaners illustrated in FIG-URE 1 to the advanced position of the lower cleaner 1B. The inner end ofthe nozzle tube is provided with nozzle apertures 7 arrangedsymmetrically around the circumference, two such apertures beingprovided in the construction shown. In operation, the nozzle tube 3,while supplied with cleaning uid, is advanced between rows of the tubes9 which are to be cleaned, and is at the same time rotated about itslongitudinal axis, so that' cleaning uid issuing from the nozzleapertures 7 scouts the outer surfaces of the tubes 9. Having reached theadvanced position, the nozzle tube is retracted, rotating now in theopposite direction.

Cleaning uid is supplied to the nozzle tube 3 from a supply pipe 11which is secured to the inlet of a pressure part 13 in the form of avalve chest. The outlet 1S from the pressure part 13 has connected to ita feed or supply tube 17. The feed tube is arranged telescopicallywithin the nozzle tube 3.

The nozzle tube is sup-ported near the wall end of the part thereofoutside the casing wall 5 within a bracket 19, through which it extends.This bracket is provided in its lower part with two freely rotatablerollers 21 which are arranged slightly on the skew with respect to thenozzle tube so that as the latter rotates and at the same timeprogresses axially a proper rolling action takes place between thenozzle tube and the rollers. The bracket 19 is in turn supported from abeam 23 of I-section extending above and parallel to the longitudinalaxis of the feed tube 17 and itself suitably supported.

The nozzle tube 3 is supported near its outer end in a carriage 25arranged to run on a track plate 26 secured to the underside of the beam23.

rEhe nozzle tube 3 has secured to its rearmost end by welding, asindicated at 27 in FIGURE 2, an annular terminal member 29 part of whichextends within the nozzle tube 3, and part of which is shaped as aportion of a sphere and is arranged to engage two annular packing ringsshown and described in detail in the above mentioned specification No.636,052. These packing rings are seated in a counter bore at the forwardend of a gland member carried by the carriage 25. A fluid tight slidingconnection between the feed tube 17 and the gland member is provided bya compressed packing. A motor 31 is mounted on the carriage 25 andeffects movement of the carriage along the beam 23 and, through the twoannular packing rings mentioned above, rotation of the nozzle tube 3about its axis.

In the construction set out in the prior specification, cleaning fluidissuing from the open forward end of the feed tube continues to ilowforwardly, along the nozzle tube, towards the nozzle apertures. In themodified cleaner of the present invention, the nozzle tube 3 includes aliner in the form of a tube 33 having a closed forward end 33A andprovided at spaced locations about its periphery and along its lengthwith outwardly extending projections 35 by which it is maintained inspaced relation to the outer nozzle tube 3. As will be seen from FIG-URES 2 and 3, an annular space 37 is bounded by the inner surfaceoftheouter nozzle tube 3 and the outer surface of the liner tube 33 andcommunicates at its forward end with the part of the outer nozzle tubeprovided with the apertures. 7 and at its rearward end with a furtherannular space 39 bounded by the inner surface of the liner tube 33 andthe outer surface of the feed tube i7. A flow path for cleaning huid isthus established extending forwardly through the feed tube 17,rearwardly through the annular space 39, and forwardly through theannular space 37 and to the apertures 7.

The projections 35 are in the form of small, shaped metal blocksextending through oblong holes cut in the liner tube 33 and welded inplace. The parts of these blocks outside the liner tube are so shaped asto ,iam against the inner surface of the nozzle tube 3 and hold theliner tube against rotary and longitudinal movement relative tothenozzle tube. lf desired, as a precaution against the forces set up bythe flow of cleaning fluid causing displacement of the liner tube 33`towards the front end of the outer nozzle tube, where it could close thefront end of the annular space 37a metal bar il can be weldedto thefront end of the liner tube 33, this bar being of such a length thatupon forward movement of the liner tube the bar will butt against asloping inner surface 3B of the outer nozzle tube and prevent movementof the liner tube 33 to a position in which the space 37 is blocked atits forward end.

The partsof the blocks 40 which extend inside the liner tube 33 areformed each with a radially inwards surface 43 which slopes inwardly andforwardly to a crest portion 45.' When the nozzle tube 3 is in itswithdrawn position, as shown for cleaner 1A in FIGURE l and as shown inFIGURE-2, the crest portions 45 engage the feed tube 17 and support itcentrally of the nozzle tube 3; When the nozzle tube 3 is movedrearwardly from the advanced position'shown for cleaner 1B in FIGURE 1,the sloping surface 43 on each block 49 causes the block to ride up ontotA e outside of the feed tube i7 without fouling its forward end.

During use of the uid heater cleaner described above, the flow ofcleaning fluid through the annular space 37 ensures that the nozzle tube3 will remain at a relatively low temperature despite its exposure tohigh temperature gases flowing through the gas pass containing the fluidheater.

By the selection for the radial width of the annular space 37 of asuitable value, the velocity of flow of the cleaning fluid flow over theinner surface of the nozzle tube 3 can be maintained at a desired highvalue, no matterl how large the diameter of the nozzle tube 3. This is iin contradistinction to the conditions in the nozzle tube of the priorspecification mentioned above in which, for any given mass flow ofcleaning fluid, the velocity of the cleaning fluid through the nozzletube varies inversely asth-e square of the internal diameter of thenozzle tube.

The rigidity of the nozzle tube as a cantilever beam varies with itsdiameter and its working temperature. With the construction of the priorspecification, an increase in the rigidity promised by an increase inthe diameter of the nozzle tube 3 is countered by a decrease in therigidity due to the increased working temperature of the nozzle tubeconsequent upon the reduced efficiency of the cleaning fluid ineffecting cooling of the nozzle tube. As a result, a limit is foundbeyond which an increase in the diameter of the nozzle tube no longerprovides an increase in the rigidity of the nozzle tube.

By the provision of the liner tube 33 and the diversion -of all thecleaning iluid to flow through the annular space between the liner tubeand the outer nozzle tube, the effectiveness of the cleaning fluid as acooling medium is improved, and the diameter of the outer nozzle tubemay be considerably increased before the increased heat absorption bythe larger surface area of the tube reaches a value too great for thelimited amount of cleaning iluid available to effect sucient cooling ofthe nozzle tube.

Ffue provisionof a more rigid nozzle,l tube permits the use of longernozzle tubes in situations where the amount of liezure of the freeforwardl end of the nozzle tube is limited by the spacing of the heatexchange tubes between which it is to extend and in situations where thelimiting factor is the ability of the nozzle to withstand the reactionof the discharge of cleaning fluid from a non-symmetrical arrangement ofapertures on the nozzle tube.

A secondary problem which arises when a very lengthy nozzle tube is usedis the support of the feed tube 17. rfhe feed tube 17 is supported atits rearward end by the pressure part i3 and at some other point by thesliding gland, but since that sliding gland moves over the outer surfaceof the feed tube it cannot be providedwith any fixed support over alength at least as large as the. distance through which the nozzle tube3 moves forwardly. The blocks di) described above provide support of thefeed'tube 17 at spaced points along its whole. length when the nozzletube 3 is fully retracted, and over a forward part of its length whenthe nozzle tube is partly advanced. This intermediate support is mostimportant during retraction of thenozzle tube, since in the absence ofany such support the forward end of the feed tube will sag onto and restupon the inner surface of the liner tube 33, and tend to scuif that tubeas it moves rearwardly.

Whenthe nozzle tube is fully advanced, the feed tube l is supported atits rearward end by the pressure part 13 and near its forward end by thesliding gland, and if unsupported will tend to sag at its mid-lengthunless it is made of large; diameter and thus rigid. A large diameterfeed tube is undesirable since it necessitates the use of a largesliding gland and a general increase in the size of the paris ofthe uidheater cleaner. FIGURES 4 and 5- show a simple intermediatesupport'member 51 which, when the nozzle tube 3 is in its retractedposition, is carried by a rearward projection 53 provided on thecarriage 25, but, as the nozzle tube reaches a predetermined position inits forward movement, is stopped by two abutments 55 fixed to the I-beam23 and left behind by the nozzle tube to act as anY intermediate supportfor the feed tube 17.

The support member 51 is in the form of a plate formed with an aperture57 the lower end of which is shaped to accommodate the feed tube 117 andthe upper end 57A of which is horizontal but rounded along its edges. Atits upper end the plate is formed with an aperture 59 in which lies thelower part of the l-beam 23A and the track plate, this aperture havingtwo shoulders til respectively on opposite sides of l-beam 23 which canengage the upper surface of the track plate so that the support memberSik is supported by the track plate. The depth of the aperture 59 issuch that the support member can be moved up to the position shown inFIGURE 5 so that the shoulders 6l disengage from the track plate. Abovethese shoulders the support member is provided with two inwardly facinglugs 63 arranged to engage respectively the two abutments 55. Therearward projection 53 is slightly narrower than the upper end of theaperture 57 and its upper surface includes a horizontal part 53Aadjacent the carriage 25 and a downwardly and rearwardly sloping part53B disposed rearwardly of the part 53A. In FIGURE 4 is indicated theposition of two forwardly facing abutments 65 which are provided on thefront face of the pressure part 13 and lie on opposite sides of theaperture 57 level with the projection 53.

in use of the fluid heater cleaner fitted with such an intermediatesupport, as the nozzle tube 3 moves forwardly the support member 51engages the abutments 55 and is left behind by the forwardly movingnozzle tube. Initially the support member is lowered as the upper end57A of the aperture 57 slides down the sloping part 53B of theprojection 53. This downward movement is stopped by engagement of theshoulders 61 with the upper-surface of the' track plate Z6. Since thefeed tube 17 is still supported adjacent the support member 51 by thesliding gland of the carriage 25, the feed tube 17 is still spaced fromand unsupported by the support member. As the carriage and the slidinggland moves away from the support member 51, the feed tube 17 commencesto sag, and cornes into contact with the shaped lower end of theaperture 57, by which it is supported.

During retraction of the nozzle tube 3, first the feed tube 17 is liftedfrom the support member 51 as the sliding gland moves towards thesupport member, then the projection 53 enters the aperture 57, andiinally the projection 53 lifts the support member out of contact withthe track plate to ytravel rearwardly with the carriage and the nozzletube. It will be seen that no sliding movement takes place between thesupport member and either the track plate or the feed tube. It mayhappen that the support member 51 does not rise fully onto the part 53Aof the projection 53; however, as the support member 51 approaches thepressure part it will be engaged by the projection 65 if it is notproperly on the projection 53, and the terminal part of the movement ofthe carriage 2S will ensure that the support member is properlypositioned on projection 53.

In the case of a very long feed tube 17, a plurality of support members51 can be provided on a single projection 53 with the abutments 55 andthe lugs 63 of the various support members arranged so that the supportmentbers are rendered operative one after the other by continued forwardmovement of the blower tube 3. This is readily arranged by a suitableselection of the transverse distance between lugs 63 and of the widthsof the a-butments 55.

What is claimed is:

1. A uid heater cleaner :comprising a nozzle tube, an inner, cleaningfluid supply tube arranged telescopically inside the nozzle tube, anozzle tube mounting accommodating the nozzle tube to permit it to beprojected from a retracted position outside a gas pass of a vapourgenerating unit to an operative position in the gas pass 'and returnedto the retracted position, means -for moving the nozzle tube between theretracted and projected positions,

the nozzle tube including an outer nozzle tube and a thin, inner linertube having a closed leading end remote from the end through which thesupply tube passes and provided with projections arranged to space theliner t-ube from the outer nozzle tube to define an axially extendingannular passage Abetween the outer nozzle tube and the inner liner tubeextending along substantially the whole of the part of the nozzle tubewhich, when the huid heater cleaner is installed and the nozzle tube isyfully projected to the operative position, lies within the gas pass,and at least one discharge nozzle provided -on the outer nozzle tubebeyond the leading end of the liner tube, the supply tube supplyingcleaning fluid to the interior of the nozzle tube to pass along theaxially extending annular passage to the said discharge nozzle, wherebyin use the desired velocity of flow of cleaning uid over the innersurface of the outer nozzle tube can be obtained despite the relativelylarge cross sectional area of the bore of the outer nozzle tube.

2. A fluid heater cleaner according to claim 1, in which the projectionsextend through the liner tube, radially outer portions of whichprojections are arranged to maintain the liner tube in suitably spacedrelation to the outer nozzle tube and radially inner portions of whichprojections -are arranged to maintain the part of the supply tube withinthe inner liner tube centrally of the inner liner tube.

3. A uid heater cleaner according to claim 2, in which the radiallyinner portions of the projections provided on the liner tube are shapedat their radially inner ends to provide ramp-like surfaces facing towarda free end of the supply tube as the nozzle tube is being retracted,whereby entry of the free end of the supply tube between the projectionsis facilitated.

References Cited in the file of this patent UNITED STATES PATENTS606,093 Semke June 21, 1898 690,474 Snyder Ian. 7, 1902 2,324,785Linaker July 20, 1943 2,668,978 DeMart Feb. 16, 1954

